You can find the right section for your fanart - listed alphabetically by webcomic - and submit directly.
Or you can submit to the main gallery and
use the dropdown menu in the pop-up submission box to select the right webcomic.
You can submit as many as you like at the moment - this may change if we get too many submissions and we start spamming people. But not right now.
I have to set approval for each folder individually, every time I make a new one, so if you find you can't submit - just comment and let me know. (This also goes for 'but why is the comic I have fanart for not there?')
Submissions are subject to vote, just so I can keep an eye on what is going into people's inboxes.
FavouritesSubmissions to favourites is open season! Go ahead

Just make sure it's in the right category. And you can submit to both gallery and faves.
The Featured folder is closed, but especially impressive work will also be copied to there.
What to submitDrawings, paintings, models, stick figures, cosplays, epic poetry... as long as it is in some way fanart of webcomics.
Blogs. You CAN write your own blog entries - it needs my approval, but as long as it's somehow related, your entires are welcome (and yes, that includes announcements from webcomic creatos

)
A webcomic artist?This isn't really a place for your comic strips - there are lots of groups for that. But your character portraits and studies and random drawings, and fanart of other webcomics? Go for it. If it's not your main comic, and therefore somehow extra, we want it.
Nifty thingsYou can submit other people's work! Just use the 'all of DeviantART' option on the submission box (they have to approve it, but that's all). So if there's a webcomic you love without enough art...
You can drag works to your group's faves in the collections dropdown! The favourites are categorised differently - fanart, original artist, cosplays, misc (do we need anything else? Guest strips? Crossovers? )